350 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[October, 



inclination of the strata is towards tlie line of rails, the slope should be made 

 at a Rreater angle than if tlie strata inclined from the rails ; if this be done, 

 fewer landslips will occur from accunuilatious of water between the strata 

 thus inclined towards the rails ; and such slips may lie further guarded against 

 bv minute and careful observation of the nature of tlie individual strata, and 

 a'scientific application of subterranean drains at the contact of each permeable 

 stratum with a subjacent bed of clay. Tunnels can be safely formed without 

 masonry in unstratified rocks of hard granite, porphyry, trap, &c., and in 

 compact slate rocks ; also in masses of tufa, such as cover llerculaneum, and 

 are pierced by the grotto of Pausilippo near Naples ; but in his opinion, wide 

 tunnels driven in stratified rock could not be considered secure unless they 

 were supported bv arches. 



Mr. Sopwith confirmed the remarks ou the importance to the civd engi- 

 neer of a knowledge of tlie geological character of the strata through which 

 tunnels or open cuttings were to be made ; the cost was materially affected, 

 as well as the stability of tlie works. The angle of inclination and the lines 

 of cleavage should be carefully studied ; on one side of a cutting the slope 

 might be left steep, and all would be firm and dry ; whilst ui the other, if 

 the same slope was adopted, all would appear disintegrated and wet, and a 

 series of accidents would be the necessary consequence. He could not sufS- 

 ciently urge the importance of a more intimate connexion between the geolo- 

 gist and the engineer. , 



In answer to a remark by Mr Farey on the apparent advantages of Frazer s 

 centres for tunnelling, Mr.' Bull promised to procure for the Institution an 

 account of the execution of some work with them. 



" An account of the Railroad constructing between Liege and Verviers, 

 Belgium" By Lieutenant Oldfield, Assoc. Inst. C. E. 



The materials for this communication were drawn from the memoranda 

 made during a tour by the author, who is an engineer officer in the service 

 of the East India Company. It describes the general course of the railway, 

 descending by the long inclined planes, from the height above Liege to the 

 valley of the Meuse, its progress along the hanks of the Vesdre, through tun- 

 nels, and over almost innumerable bridges and viaducts, to Chaudfontaine, 

 and thence onward through the town of Verviers, in the direction of Aix-la- 

 Chapelle, to the frontiers'of Germany. The modes of excavating the tunnels, 

 and the materials used in the other works on the line, are accurately de- 

 scribed ; the general acclivities and curves of the road, the rails, chairs, and 

 methods of fastening them to the sleepers, and the prices of labour and ma- 

 terials, are all given in detail, and the whole was illustrated by enlarged dia- 

 grams from the author's sketches. 



May 10. — The President in the Chair. 



" Description of a Fla.r Mill recently erected by Messrs. Marshall and Co. 

 at Leeds." By James Combe, Assoc. Inst. C. E. 



The mill described in this communication consists of one room, 396 feet 

 long by 216 feet wide, covering nearly two acres of ground. The roof is 

 formed of brick groined arches 21 feet high by 36 feet span, upon cast-iion 

 pillars : an impermeable covering of coal-tar and lime is laid on a coating of 

 rough plaster over the arches, and upon that is a layer of earth 8 inches 

 thick, sown with pr.iss. This immense room is lighted and ventilated by a 

 series of skylights 13 feet 6 inches diameter ; one at the centre of each arch. 

 A vaulted cellar with brick pillars extends under the whole of the building, 

 and contains the shafts for communicating the motion from a pair of engines 

 of 100 horses' power, to the machinery in the mill ; the flues and steam 

 cases for warming and ventilating ; the revolving fan for urging the air into 

 the room, with the gas and water pipes, and the remainder of the space is 

 appropriated for warehouses. 



The heating and ventilating arc effected by a large fan, which forces the 

 air through the pipes of two steam chests, each 10 feet long, and containing 

 together 364 pipes of 3^ inches bore : the temperature can be regulated by 

 the quantity of steam which is admitted into the chests, or by allowing a 

 portion of cold air to pass by without traversing the pipes ; valves and doors 

 in the flues permit any temperature which is desired to be obtained, or that 

 degree of moisture which is essential for some part of the process of work- 

 ing flax. The general details of the construction of the building are given 

 with the dimensions of the brick and stone work ; the cast-iron pillars and 

 caps, the wrought-iron tie-bars, with the reasons for adding a second set 

 after the accident occurred to the first set ; the mode of drainage from the 

 roof; and the striking the centres of the arches, &c. 



The total cost of the mill including the ornamental stone front was £27,443, 

 which is stated to be about the same cost as that of a good fire-proof mill 

 on the common plan ; but as this mode of construction was novel to the 

 workmen, it is probable that a second building of the kind would be less 

 expensive. The advantages resulting from the plan are, convenience of 

 supervision, facility of access to tlie machines, the power of sustaining uni- 

 formity of temperature and moisture, the absence of currents of air which 

 are so objectionable in other mills, the simplicity of the driving gear, and 

 the excellent ventilation which is so desirable for the health of the work- 

 people. 



The paper was illustrated by two drawings with a sheet of reference, and 



an appendix contained the result of some experiments upon the strain on 

 the tie-bolts, the pressure on the arches, and the deflexion of the bolts, &c. 



Remarks. — Mr. Smith, of Deanston, was much pleased to find this des- 

 cription brought before the Institution, as he was the first to adopt it for a 

 weaving shed of the extent of half an acre ; the columns for carrying the 

 arches were 30 feet six inches apart, and the skylights were 8 feet in dia- 

 meter ; some of the arches were of brick, with stone springers ; others were 

 entirely built with rubble stone well grouted, which latter mode of con- 

 stniction he found succeeded quite as well as brick : the settlement of the 

 arches on striking the centres after standing four days was only ifths of an 

 inch : The arches were thickly plastered with common mortar and at first 

 were only covered with a coating of boiled coal-tar pitch, and lime fths of 

 an inch thick, but as the wet penetrated, the thickness of coal-tar pitch was 

 increased to fths of an inch, with a mixture of sharp sand, which had 

 proved perfectly water-tight : for some months there was an appearance of 

 moisture, which proceeded from the interior of the brickwork, as it could 

 not escape outwards ou account of the impermeable covering ; after some 

 time the copious ventilation carried off this moisture and the building be- 

 came perfectly dry. Over the coal-tar a thickness of earth is laid, which is 

 cultivated, and has proved a prolific garden : in severe weather the frost has 

 not reached above lA inch deep in the soil, while it has penetrated to the 

 extent of 12 inches in other situations. The construction of the floor is 

 peculiar : it is desirable in such weaving sheds to have a boarded floor, to 

 prevent the small parts of the machinery from being broken by falls, and 

 also on account of the health of the persons employed ; but the vibration of 

 an ordinary wood floor is objectionable. In order to meet these views, a bed 

 of concrete was laid throughout the building, a series of small deal spars 1^ 

 inch deep by one inch wide were set flush into the concrete whilst it was 

 wet, and the whole surface was smooth plastered : upon this bed, when it 

 was perfectly dry, a floor of boards Uth inch thick was nailed to the spars : 

 it was found' to combine the solidity of pavement with all the advantages of 

 a wood floor, and there had not been any symptoms of dry rot : which might 

 be attributed to there being no cavities left beneath the boards, the whole 

 being firmly bedded down. The ventilation was eft'ected by tunnels beneath 

 the floor, the covers of which were pierced with a number of small holes to 

 spread the air. The warming was accomplished by means of hot water cir- 

 culating under the pressure of the atmosphere only, in " tubeS of tin plate" 

 4 inches diameter ; the temperature was very regular and perfectly under 

 control. With one ton of coal per week the shed could be kept up to 70° 

 during the winter. The cost of this building was 30 shillings per square 

 yard of area covered, which was less than the cost of Messrs. Marshall's 

 mill, but building materials were much cheaper at Deanston than at Leeds. 

 He expected that this mode of building would become more general as it 

 combined many advantages, and whatever might be the first outlay in pur- 

 chasing ground, the cost of which was the only inducement for constructing 

 buildings of several stories in height, it would be fully compensated by the 

 facility of superintendence alone, as in manufactories this was of the utmost 

 importance. These buildings would, he believed, be eventually used for ag- 

 ricultural purposes, and when engineering knowledge was more directed to 

 the processes of agriculture, good results might be anticipated : his attention 

 had been particularly directed to the subject, and he was convinced of the 

 necessity of concentrated superintendence which is not at present possible in 

 the separate farm-steadings as they are now constructed : this might be ap- 

 parently foreign to the subject before the meeting, hut the range of engi- 

 neering was so wide that it was difficult to say where it should stop. 



Mr. Lindsay Carnegie as a landed proprietor could bear testimony to the 

 importance of' the connexion of engineering with agriculture, and to the ad- 

 vantages already derived from the improvements which had been introduced 

 by Mr. Smith, who might be justly termed the father of the improved system 

 of agriculture in Scotland. 



Mr. Marshall explained that he was indebted to Mr. Smith for the sug- 

 gestion of this mode of construction, which he had not hesitated to adopt 

 although all the plans had been prepared for mills of several stories in 

 height — he had been convinced of the superiority of the present plan and 

 his expectations had been fully realized. There were of course some diffi- 

 culties to be overcome and some experiments to try, all of which had not 

 been successful, but in all the essential points this kind of building was su- 

 perior to any other. An equality of temperature and a facility of imparting 

 a certain degree of moisture to the air which was indispensable for spinning 

 yarn had been perfectly attained. 



Mr. Braithwaite inquired whether the arches were found to be perfectly 

 water-tight ? On some of the railways which were laid upon arches it 

 had been found that asjihalte had faile'd in rendering them impervious, and 

 they were consequently useless, even for store-houses. 



Mr. Marshall explained that a few leaks had occuiTed, particularly near 

 the skylight-frames, hut they had been easily repaired and were now water- 

 tight. . 



Mr. Combe found that a mixture of finely-sifted engine ashes with the 

 coal-tar pitch was better than lime. The depth of soil above the arches 

 should be sufficieut to prevent the heat of the sun from penetrating through 

 the cracks to the pitch and forcing it up. He hatl recently examined the 

 roof carefully and could only discover six indications of moisture penetrating; 

 these had been easily repaired and all was now perfectly sound. 



Mr. Field agreed' with Mr. Smith in his estimation of the advantages of 

 carrying on all manufacturing processes as much as possible under one roof 

 and'on one floor— great economy of time and labour would result, especially 



